The invention relates to a printing method for printing a variety of information such as images and characters on a recording medium, such as a card. More particularly, the invention relates to a printing method capable of switching printing methods according to characteristics of a recording medium or information for printing a variety of information.
Conventionally, a thermal transfer printing apparatus has been used to record a desired image or a character on a card recording medium such as a credit card, a cash card, a license card or an ID card by thermally transferring with a thermal head via a thermal transfer film. As an example, in Japanese Patent Publication (KOKAI) No. 09-131930, a printing apparatus using a direct transfer method has been disclosed. The apparatus directly transfers an image and a character to a recording medium via a thermal transfer film. This method has an advantage of attaining a high quality image due to thermal sublimate ink. However, the recording medium needs to have a receptive layer on its printing surface to receive the ink. Therefore, only limited recording medium can be used, or the receptive layer needs to be formed on the surface of the recording medium.
Generally, a card made of a polyvinyl chloride (known as a PVC card) has been widely used as the recording medium that can receive the thermal sublimate ink. However, since the PVC card generates toxic substances when burned, recently it has been tried to switch to a card made of a polyethylene terephthalate (also known as a PET card).
Furthermore, in recent years, a new type of card media such as an IC card, which embeds an IC chip or antenna inside, has been used in a variety of fields. Because of the embedded elements, this type of card has an uneven surface, resulting in a printing problem.
In Japanese Patent Publication (TOKKAI) No. 08-332742, a printing apparatus using an indirect transfer technology, in which an image is transferred to an intermediate transfer medium after the image is transferred to a final recording medium, has been disclosed to solve the above problem. According to this method, it is possible to overcome the problems such as limited recording medium related to the receptive layer or the issue of printing on an uneven surface of the recording medium. Furthermore, this method makes it easier to print an image on an entire surface of the card medium as opposed to the direct transfer method.
However, in the intermediate transfer method, a running cost tends to be higher than that of the direct transfer method because of the intermediate transfer medium. Also, it takes longer time to finish printing. Furthermore, in terms of a card design, there are many cases where a front side needs to be printed on a whole area while only limited area such as precautions for card use is needed to print on a backside. Thus, there are merits and demerits for both printing methods. Therefore, it is possible to reduce a running cost by selecting a method most appropriate to a recording medium if a printing apparatus can switch between the direct transfer method and the indirect transfer method to print an image on a recording medium depending on an objective of printing. It is expected that such a printing apparatus will be used more widely in the future.
However, a printing apparatus that can apply the two printing methods requires a complex printing process, resulting in an increase in processing errors of the printing process.
An object of the present invention is to provide a printing method that can switch between the direct transfer method and the indirect transfer method for printing, thereby reducing problems associated with the printing process.
Another object of the present invention is to provide a printing method that reduces mechanical errors and failures inside of the printing apparatus while improving printing capacity such as a processing time or throughput time per specific number of the media.
Further objects and advantages of the invention will be apparent from the following description of the invention.